I use a local pre-populated database file (added in the project folder) in order to access the needed data. In order to make it work with SQLiteAsyncConnection, one should change the attribute "Build Action" (to "Content") in the properties of the file.
That change is easy when it's a local file added in the IDE.
What about a downloaded database file?
I downloaded a new version of my database and stored it in the IsolatedStorage. When I try to query this db, I get an "SQLiteException" error -the same that I was getting in case I had forgotten to change the above mentioned property.
Any suggestion on that?
Related
I am fairly new to C# and I was wondering how to keep an XML file from being overwritten if one already exists on the install. In the application, there are two files that contain info to connect to the Database. One of them is relatively dynamic, but the other is saved at the setup. If I do a publish and try to update the application it always overwrites both files. Any thoughts?
You can check if the file exists with File.Exists(Path)
You can look here for more information:
https://learn.microsoft.com/en-us/dotnet/api/system.io.file.exists?view=netcore-3.1
If this does not work you can try to read that file and if there is any data there just sont delete it.
I assume you are refering to configuration settings.
While designing your settings, in the designer, set scope to "User". This will bind the setting to the users local app settings, and will not be overwritten.
More info here: https://learn.microsoft.com/en-us/dotnet/framework/winforms/advanced/how-to-create-a-new-setting-at-design-time
I am creating a library application in Visual Studio 2010 Professional and Access 2010. I bind the Access database to Visual Studio. When I fill out the fields and click submit I can see the new record in the DataGridView, but when I close the application the new record is not saved and I have to input the record again.
Can somebody help me to know why when I input the new record through the application the record is not saved in the database?
It is a very common situation. You have your database file (the MDB or ACCDB file) listed between your project items. If you click on this file and look at the properties window you will see a property called Copy to the output directory. If this property is set to Copy Always then every time you start a debug session the database file listed in your project items is copied by VS in the output directory (usually BIN\DEBUG). Of course this copy doesn't contain the records inserted in your last debug session and you think that your previous insert has failed.
Setting this property to Copy If Newer, the mentioned behavior will happen only if you change the database schema manually.
Setting this property to Copy Never, will let you manually copy the database file.
I have a C# app which reads from and writes to an Access database. There is one database file per user. My intention is to check for the existence of the MDB in the user's My Documents folder at launch, and if the MDB isn't found, then copy the template MDB to that folder.
I have already added the template MDB to my project and placed it in its own folder which I have called Packaged. However, I am unable to refer to this Packaged folder from code as it doesn't appear in IntelliSense.
My intention had been to use File.Copy to copy the MDB over, but I cannot determine the file path as I can't access the MDB in code. And presumably it wouldn't have a file path anyway if it's just packaged in the .exe?
What would be the best way to achieve this, given that I would rather not distribute a separate MDB if possible?
I've done this in the past by making the MDB an embedded resource, and writing it to disk as needed (if it doesn't exist).
Here is more info on writing an embedded resource to file.
You'd almost have to use one of the Environmental paths for the template MDB. Like ApplicationData or Documents and Settings\Username\Local Settings\ or one of the other ones. Local User Data is the best way for user specific data. IN the code in the beginning, determine to see if the file exists in the first run. If it exists copy the template, if not don't.
That way the user has full read and write access and the ability to copy the file or duplicate the file without security problems. These environmental variables are accessible through
Environment.GetEnvironmentVariable
You could also have a registry setting and read and write to the registry for that specific application, that has a simple DatabaseAvailable key, and toggle it yes or no.
You could also embed the MDB as a resource too, and then write it as necessary.
I have a database that I connect as a file, i.e. through the AttachDBFile attribute in ConnectionString in web.config file of ASP.NET site. The database is in the App_Data folder od the website. I made a small app, that should allow to copy paste (a kind of backup functionality) the database to any chosen directory. For this I am using FileDialog box for allowing the user to chose the destination directory. I am using the .NET FileSystem API for copy pasting. The problem is that, I cannot copy paste the database till I shut down the SQL Express service. During copy, a dialog saying that the file is currently under use by other process is shown. If I turn off the service I can copy paste the database.
I used AttachDBFile attribute, since I thought that it will allow such copy, since this doesnt directly attach the database to the server. But now I think its not like that. :(
So how I can deal with this. Please help. Thank you.
You get the error since the file is locked while it's in use.
Have a look at the recommended ways to backup your database at msdn: http://msdn.microsoft.com/en-us/library/ms187510.aspx.
We are working with two different teams on the same project. In a configuration file App.config, we have two connections string with our connection settings to connect to our database and the second team has another database with a different connection string. I have to comment the second connection string and uncomment the first. I have to check always this file if the connection string is correct (if the another team has not commited this file). It's a little bit boring..
This configuration file contains some other configurations keys that we use in common. My goal is to set (on the config file with a or somewhat) to tell to SVN to not include this part of file when I made a commit.
Is it possible ?
Partial file commits aren't possible in any version tracking system I've ever seen. You can however take a look at something like this if you're using VS2010.
You can use the configSource attribute to have ASP.NET read the config from an external file instead of the main config file. That way you can have one dirty and ignore-on-commit file containing the connection strings, and still be able to commit the main config file when changes are needed.
I suggest that everyone in your teams backup the configuration file, and have someone rename the file in SVN to something like template.[original-name] and commit that.
Then, have everybody restore their own configuration file and put in into the svn:ignore Subversion property of the directory containing the file, and commit that directory to have the svn:ignore in version control for everyone and have them update their working copies after that.
This way, each team member can have a different configuration.
Configuration and user/system specific files should not be in version control.
See also http://svnbook.red-bean.com/nightly/en/svn.advanced.props.special.ignore.html.
EDIT: To actually answer your question, David is right, partial file commits are not possible (and usually would not make sense either). It is not the intended workflow of Subversion.